Releasable stop means for a movable unit in a stationary enclosure



June 8, 1965 A. M. BOYDEN 3,183,414

RELEASABLE STOP MEANS FOR A MOVABLE UNIT IN A STATIONQRY ENCLOSURE 6 Sheets-Sheet 1 Filed May 14, 1962 wvz/vrons A LBERT M 50 YDEN,

CONNECTED DISCON/VECT BY MS.

ATTORNEY.

A. M. BOYDEN RELEASABLE STOP MEAN 3,188,414 s FOR A MOVABLE UNIT IN NARY ENCLOSURE June 8, 1965 A sumo Filed May 14, 1962 6 Sheets-Sheet 2 /NVENTOR. ALBERT M 50 YDEN,

BY mm- 5. ATTORNEY.

June 8, 1965 A. M. BOYDEN RELEASABLE STOP MEANS FOR A MOVABLE UNIT IN A STATIONARY ENCLOSURE Filed May 14, 1962 6 Sheets-Sheet 5 D/SGO/VNECT INVENTOR.

A TTORNE).

. ALBERT M. BOYDEN,

June 8, 1965 A. M. BOYDEN 3,188,414

' RELEASABLE STOP MEANS FOR A MOVABLE UNIT IN A STATIONARY ENCLOSURE 6 Sheets-Sheet 4 Filed May 14, 1962 June 8, 1965 A. M. BOYDEN RELEASABLE STOP MEANS FOR A MOVABLE UNIT IN 'A' STATIONARY ENCLOSURE 6 Sheets-Sheet 5 Filed May 14, 1962 m, o I m B fi R0 Y. M U w l: w H L m 6 A J a) F Y m a w a I 2 c 6 Wwe M '4, W l N a 0 WV: w ur! If A; v; r'lala wwvlaa 1 June 8, 1965 A. M. BOYDEN 3,188,414

- RELEASABLE STOP MEANS FOR A MOVABLE UNIT IN A STATIONARY ENCLOSURE 6 Sheets-Sheet 6 Filed May 14, 1962 INVEN TOR ALBERT M. 80 yoz/v, 5y Cwbczk W ATTORNEY.

United States Patent 3,188,414 RELEASABLE STOP MEANS FGR A MOVABLE UNIT IN A STATIONARY ENCLOSURE Albert M. Boyden, Upper Darby, Pa., assignor to General Electric Company, a corporation of New York Filed May 14, 1962, Ser. No. 194,360 7 Claims. (Cl. 200-50) This invention relates to releasable stop means for a movable unit in a stationary enclosure, and more particularly it relates to a mechanism including stop means and related parts for controlling the movement of a drawout circuit breaker unit in metal-enclosed electric switchgear.

A movable unit of the kind contemplated herein is utilized to support objects or equipment in an appropriate enclosure or housing so that such equipment can be conveniently withdrawn from the enclosure for purposes of access thereto. The movable unit is ordinarily arranged for reciprocating movement along a given course between an inserted position within the enclosure and a withdrawn position wherein the supported equipment is readily accessible. It is customary to provide suitable stop means for detaining the movable unit in each of its inserted and withdrawn'positions, and sometimes in at least one other predetermined position therebetween. Hence the movable unit cannot be moved from each of of the positions so defined until a deliberate stop-meansreleasing operation is carried out. A general object of the invention which is described and claimed hereinafter is tovprovide apparatus of thisv kind wherein the stop means and the meansfor releasing the same cooperate in a novel and improved manner which enhances operating convenience.

My invention is particularly useful in conjunction with movable units which are'adapted to supportyelectric circuit breakers. A wide variety of mechanisms have been designed'for inserting and withdrawing a movable circuit breaker with respect to a stationary enclosure or compartment. In such mechanisms it is common practice to include interlock means for permitting movement of a circuit breaker only when its circuit-interrupting contacts are in an open circuit condition. Another object of the present invention is the provision, for a circuit breaker drawout mechanism, of improved stop means and means for releasing the same which incorporate this conventional interlock function.

The illustrated embodiment of my invention has previously been disclosed in a copending patent application S.N. 154,960, filed for Philip C. Netzel on November 27, 1961, and assigned to the assignee of the present application. In that application a unique housing for a removable circuit breaker is claimed, and in one aspect of its teachings the housing includes position stop means which operates to block movement of the circuit breaker and simultaneously to disable a racking mechanism which is provided to drive the breaker unit along its course of reciprocating movement. The position stop means disclosed in the Netzel application is released or reset by i a mechanism which is the claimed subject matter of the to an enclosure unit, and releasable stop means is disposed in cooperation therewith for stopping the movable unit in a predetermined position relative to the enclosure unit. The stop means operates automatically when the movable unit reaches its predetermined position to prevent continued movement ocf that unit until released. In

3,188,4l4 Patented June 8, 1965 order to release the stop means and thereby permit movement of the movable unit from its obtained position, I provide manually operative reset means, and in association with the reset means I provide means effective upon stop-means-releasing operation thereof for maintaining the stop means released so long as the movable unit remains in its obtained position. With this arrangement the operator, after operating the reset means to release the stop means, will have both hands free for conveniently resuming movement of the movable unit to another position.

In one aspect of my invention, the movable unit is adapted to support an electric circuit breaker and appropriate interlock means are associated with the aforesaid reset means for preventing stop-"neans-releasing operation thereof when the circuit breaker is closed and for preventing closure of the breaker subsequent to. said operation of the reset means and before the movable unit reaches another predetermined position.

My invention will be better understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevational View, partly broken away, of a l t-compartment enclosure for removable electric circuit breakers, with the respective circuit breakers being shown in three different positions;

FIG. 2 is a front elevational view of the enclosure of FIG. 1, with the doors of the upper and lower compartments open and with the circuit breaker removed from the lower compartment;

FIG. 3 is a simplified exploded perspective view of the upper compartment and circuit breaker shown in FIG.

FIG. 4 is a partial side elevational View of the lower compartment shown in FIG. 1, with the circuit breaker fully withdrawn therefrom;

FIG. 5 is an enlarged sectional view of the lower breaker compartment taken along lines 55 of FIG. 2 to illustrate a preferred embodiment of my invention;

FIG. 6 is a sectional view similar to FIG. 5 showing the breaker supporting means in a different disposition;

FIG. 7 is an enlarged sectional view of the upper breaker compartment along lines 77 of FIG. 2;

FIG. 8 is an enlarged sectional view of the compartment racking mechanism along lines 88 of FIG. 5;

FIG. 9 is a sectional view of my improved position stop means taken along lines 9-9 of FIG. 8;

FIG. 10 is a view similar to that of FIG. 9 with the position stop means in a released disposition;

FIG. 11 is an enlarged sectional view of the breaker compartment along lines 11-11 of FIG. 5; and

FIG. 12 is an enploded'perspective View of the interconnected members and linkages which comprise I the stop means and associated reset means of my invention, shown in their FIG. 6 dispositions.

Referring now to FIGS. 1 and 2, there is shown a stationary sheet-metal housing or enclosure 11 for electric apparatus comprising three vertically stacked individual compartments or units 12, 13 and 1 4. A pair of upstanding metal side sheets 15 and 16 and a vertically disposed rear barrier 17 form three sides of each of the generally cubic compartments r1244. Horizontal plates or barriers 1'8, 19 and 20 provide bottom closures for the respective compartments. The top closure of compartment 12 is provided by the barrier 19; the top closure of compartment v13 is provided by the barrier 20; and the top closure of compartment 14 is provided by still another horizontally disposed metal barrier 21. Each of the compartments has an opening at its front. The enclosure 11 is topped by a trim plate 22 as shown. 1

In accordance with the teachings of the copending or stationary enclosure unit comprising the housing 11 includes between its sidewalls a retractable inner part 101. Since this inner part as illustrated is identical in all three compartments, the same reference numeral 101 has been used to identify it in each instance. The inner part 101 in simplified form is best seen in FIG. 3 which is an exploded perspective view of the compartment 14. It comprises a short metal collar 102, disposed telescopically to fit into the rectangular opening of the associated compartment, and a pair of prallel, elongted supporting members or runners 103 and 104 to which the collar 102 is rigidly fastened by rivets 105 or the like. The runners 103 and 104 are integrally attached to opposite walls of the compartment 14 for movement relative thereto, and consequently the collar 102 can be extended out in front of the compartment sidewalls but is not removable therefrom. The whole inner part 101 is able to undergo reciprocating movement through the compartment opening between an initial or retracted position within the compartment (see compartment 14 in FIGS. 1 and 7) and a final or extended position partially without the compartment (see compartment 12 in FIGS. 1 and The cooperating inner part 101 of each stationary com partment, as it moves in between the above-mentioned retracted and extended positions, traverses a predetermined intermediate position (see compartment 13 in FIG. 1). The significance of this intermediate position will be explained hereinafter. For the purpose of visually indicating when the inner part is in its extended position and when it is in the predetermined intermediate position, a pair of parallel lines D and T of different lengths are located on the left side panel 102a of the extensible collar 102, as is shown in FIG. 1. Both of the lines D and T,

which may be appropriately labeled, are hidden by the side sheet 15 and therefore are entirely out of sight whe the collar is retracted. I

Each of the inner parts 101 of the enclosure 11 supports an openab'le cover 106 which provides access to the acsociated compartment. Preferably the access cover is a metal door hinged at 107 to the front edge of the right side panel 10212 of collar 102, as is shown in FIG. 3. The door 106 carries a latchbar 108 from which a pair of pins 109 laterally extend ((FIG. 4) for entering, respectively, two notches 110 formed at ditferent elevations in the front edge of the left side panel 102a of collar 102. The latchbar 108 is connected by means of an angle iron 111 or the like to an appropriate door handle 112 which is located on the front side of the door106 (see FIGS. 1, 2 and 6); the door is unlatched and swung open by manually raising and then pulling on handle 112. From FIG. 3 it is apparent that the collar 102 in effect comprises a door frame for the compartment door 106.

Whenever the compartment door is shut it completely closes the collar 102 and hence covers the front opening of the associated compartment, whereby the contents of the compartment are safely confined behind the metal shield which the door provides. The door 106, being atached to the collar 102, travels with the inner part 101 of the compartment as it is moved to its extended position. Although the collar and door then protrude in front of the compartment, the enclosed apparatus is not exposed but remains substantially wholly enclosed because the top and bottom panels and the side panels 102a and 10% forming the collar 102 will bridge the gap left between the door 106 and the front edges of the stationary walls 16, 16, and 22 of the compartment. Consequently the apparatus which the compartment houses can be safely stored in an isolated state with the inner part 101 extended, collar 102 in conjunction with the door 106 serving to protect operation personnel as well as to prevent contamination of the apparatus by dust and the like.

In the illustrated embodiment of my invention, the apparatus which each compartment 1214 is designed to receive comprises an electric circuit breaker or interrupter identified generally by the reference numeral 201. The circuit breaker 201, which may be of any standard construction, has an operating handle 202 protruding from its front escutcheon for manual actuation thereof. As indicated most clearly in FIGS. '1 and 2, the handle 202 projects through an appropriate aperture in the compartment door 105 for convenient operation from in front of the housing.

Preferably the circuit breaker 201 is supported and guided for movement by the retractable inner part 101 of the breaker compartment, whereby the breaker moves in concert with the inner part throughout the limited course of reciprocating movement thereof. In order to support the breakers, the inner part 101 is equipped with two sets of rollers 113 and 114 carried by the runners 103 and 104, respectively, for receiving a pair of rails 203 and 204m which the circuit breaker 201 is removably disposedp See FIGS. 3, 5-7 and -11. There are two pairs of spaced apart lugs or pins 205 and 206 protruding laterally on opposite sides of the circuit breaker, and these pins are received, respectively, in appropriate recesses 207 and 208 provided in the top edges of the rails 203 and 204, as

shown.

The circuit breaker 201 and the rails 203 and 204 on which it is'mounted, all moving as a unit, can be slidably inserted and withdrawn with respect to the runners 103 and 104 of the compartments inner part [101. The circuit breaker unit, once placed [between the respective rollers of the companion roller sets 1 13 and1114 which the runners carry, is firmly yet removably supported by the runners for joint movement therewith. For this purpose each of the runners 103 and 104 is preferably provided with a locking lever 115 which is pivotally attached at 116 to the runner near the forward end thereof. As is clearly shown in FIGS. 5-7, the locking lever has a generally L- shaped configuration, and a cammihg surface of its lower arm is disposed to bear against the foremost pin 205, 206

protruding from the circuit breaker 20.1 in a manner securely to wedge the removable unit between the lever 1'15 and an abutting block 117 which is affixed to the rear end of each of the runners 103 and 104. In this disposition the lever 115 also locks the circuit breaker 201 to its rails 203 and 204.

By opening the compartment door 106 and then pulling forward manually on the upper arms 115a of both of the pivotally mounted locking levers .11 5, the lower. arms of these levers will be raised from engagement with. pins 205 and 20 6, thereby releasing the circuit breaker unit for withdrawal from the enclosing compartment to a positign in which it is shown in FIG. 4. From this withdrawn position it is a simple matter to lift the crcuit breaker 201 from the rails 203 'and 204 and remove it from the enclosure for maintenance, repair or replacement purposes.

As is taught in the aforesaid Netzel application special interlock means are provided to prevent the installation of the removable circuit breaker unit in a compart ment of the housing except when the retractable inner part .101 of that compartment is in its fully extended position. The interlock means referred to, as can be seen in FIGS. 57, preferably comprises a pair-of. generally L-shaped interference levers 23 pivotally attached at 24 to 'left and right hand sidewall brackets 25 and 26, respectively, of the stationary breaker compartment, in cooperration with a pair of pins projecting inwardly fromthe extensible runner-s 103 and 10:4 and another pair of inwardly projecting pins 209 which are afiixed to the breaker rails 203 and 204, respectively. The pins 209 are at a higher elevation than the pins 118 which in turn are higher than the points 24 of pivotal attachment of sociated pins 118 and 2%. The arm 23a cannot be moved rearwardly from this upright position because the lower arm of the .lever 23 has been provided with a laterally projecting tab or pin 23b which overlays a stationary flange 25a, 26a of the adjacent sidewall bracket 25, =26, thereby blocking such movement. Consequently, assuming that the breaker unit were removed from the compartment, so long as the interference levers '23 are in their normal dispositions the return of the removable unit is blocked by the upright arms 23a whose forward edges will be engaged by the pins 299, respectively, to prevent full insertion of the rails 2% and 204 int-o the runners 103 and i164, respectively.

The interference levers 23 quit their normal dispositions and will not impede the return of the breaker unit to its supported position on runners 1% and 1% whenever the movable inner part 161 of the compartment is in its extended position (shown in FIG. 5). This disabling of the interlock means is accomplished by the action of the pins 118 which travel forward with the runners 'from which they project and, just as the retractable inner part 101 of the compartment closely approaches its extended position, move into engagement with the rear edges of the upper arms 23a of the levers 23, whereby both arms 23a are tilted frontwardly and held by the pins 118 in a position which is below the path of movement of the breaker rail pins 209. It is apparent that so long as the inner part 101 remains in its extended position, the levers 23 will not interefere with the ingress of a removable breaker unit.

Turning again to FIG. 1, the breaker units accomm dated by the housing .11 are seen to include spring-loaded primary disconnect members 216 which are aligned, respectively, with stationary primary disconnect members 27 mounted on insulating bases 28 suspended from the rear walls 17 of the breaker compartments. in cam compartment the disconnect members 21b and 27 are interengaged whenever the inner part 1691 which supports -the'circuit breaker 201 is retracted (see compartment 14 in FIG. 1), while they are separated and hence disconnected whenever the inner par-t has been extended as far as its intermediate position (see compartment 13 in FIG. 1). These cooperating primary disconnect members enable the circuit interrupting contacts (not shown) of each circuit breaker 20 1 to be electrically connected to supply and load circuits 29 and 3%) respectively, whereby the flow of elecetric power to the load circuit is controlled by operation of the circuit breaker contacts. The equipment illustrated is used most commonly for controlling and protecting S-phase power circuits; hence 3-pole breakers are used, and each compartment has three pairs of disconnect members 27, as is shown in compartment 12 in FIG. 2.

Circuit breakers of the kind illustrated are often equipped with suitable mechanisms for electrical operation thereof. .That is, the breakers include devices such as motors, solenoids and the like for the purpose of opening and closing their circuit interrupting contacts in response to operation of suitable control switches (not shown) located locally or remotely therefrom. Such devices must be connected to appropriate control wiring and circuits in the housing 11, and for this purpose separable secondary disconnect members are provided, as shown, by wayof example, in FIG. 1 at 211 and :31. A secondary disconnect member 211 comprising a plurality of upstanding, yiel-da'ble conductive fingers is carried by each removable circuit breaker unit on top thereof, and a secondary disconnect member 3-1 having a plurality of spaced-apart conductive bars depends from each horizontal barrier 19-21 of the stationary enclosures. In each of the compartments the respective conductive elements of these cooperating members are slidably interengaged so long as the inner part 1&1 of the compartment is in either its retracted or its intermediate positions (see b compartments 14 and 13 in FIG. 1), but they become disconnected upon movement .of the inner part to its are respectively interconnected and the circuit breaker 261,

is energized, (2) an intermediate or rest position of the breaker unit in which only the secondary disconnect members are interconnected, and (3) a disconnect or storage position in which all of the cooperating disconnect members are separated and the breaker 2M is entirely deenergized. The purpose of the above-mentioned intermediate or test position (which is positively defined by position stop means to be described hereinafter) is to allow testing of the breakers electrical operation without energizing the load circuit 3% each time the interrupting contacts of the circuit breaker being tested are closed. The interlock means comprising the interference levers 23 and the pins 133 and 299, as previously described, serves to prevent the removable unit from being pushed back to its fully inserted or operating position except in conjunction with a retraction of the inner part 191 of the breaker compartment. It has been noted hereinbefore that the retractable inner unit or part 101, which supports the circuit breaker 261 and carries it between the preselected positions reviewed above, is telescopically attached to the walls of the breaker compartment. Toward this end, two sets of rollers 33 and 34 are mounted on the stationary sidewall brackets 25 and 26, respectively, for receiving the two runners lit-3 and 1134 on which the collar 102 of the inner part 161 is mounted. See FIGS. 3, 5-7 and 11. As is best seen in FIGS. l-3 and 6, the top and bottom panels of the collar 1&2 are both slotted to accommodate a pair of stationary guide pins 35 and 36 which have enlarged heads and project vertically a short distance from the top and bottom closures, respectively, of the associated compartment. In order to aid in driving the collar 102 and its supporting runners 193 and- 164 through the limited course of reciprocating movement thereof, and thereby move the circuit breaker unit between its operating and storage positions, a suitable racking mechanism i provided.

The illustrated racking mechanism comprises a pair of orbital camming members or cranks 37 and 38 which are anchored to stationary walls of the breaker compartment in motion transmitting relationship with the breaker supporting runners M93 and 104, respectively. The members 37 and 3o preferably comprise ratchet wheels or disks respectively keyed to opposite ends of a common shaft 39. As is shown in FIGS. 1 and 2, the rotatable shaft 39 horizontally spans the rear of the associated breaker compartment, and it is journaled near both ends in stationary plates 4%? (FIG. 8) which are appropriately affixed to the compartment walls in spaced relation to the sidewall brackets 25 and 26, respectively.

The ratchet wheel 37 is aflixed to the left end of the shaft 39 between bracket 25 and plate 40, and it is located immedately adjacent to the block 117 which is fastened to the rear end of runner 1&3. This Wheel carries an eccentric cam roller 41 which projects laterally therefrom into a generally vertical camming slot 119 formed in the block 117, as can be seen in FIGS. 5, 6 and 8. At the right end of the common shaft 39 the ratchet wheel 38 is positioned immediately adjacent to the block 117 which is affixed to the rear end of the runner 104, and it has an eccentric cam roller 42 projecting laterally therefrom into a generally vertical camming slot 120, shown in FIG. 7. The height of each of the camming slots 119 and 120 is slightly greater than the diameter of the path circumscribed by a cam roller. As the camming members 37 and 33 rotate, their rollers 41 and 42 will orbit in unison about the fixed axis of the connnon'shaft 39, riding up and down in the associated camming slots I19 and 120 of the respective blocks 117 which the rollers inseparably engage. The resulting coaction between these cooperating elements will translate the runners Iii?) and 194, and hence the Whole inner part 161 is moved or racked from its retracted position in the breaker compartment to its extended or protruding position and back.

In order to rotate the camming members 37 and 38, the racking mechanism includes operating means having sufficient mechanical advantage to enable a persion of ordinary strength to carry out the racking operation manually with the exercise of only a reasonable amount of physical effort. Preferably the operating means comprises a T-handle 3011 which is operatively coupled to the rotatable ratchet wheel 37 by means of a flexible cable 43, a system of pulleys 44, a pivotally mounted lever 45, and a pawl 46.

As can be seen in FIGS. and 6, the pawl 46 is a long curved arm pivotally mounted between its ends on a pin 47 which is carried by one end of the lever 45. The head of the pawl is provided with a hook 4611 for driving the peripheral teeth 37a of the ratchet wheel 37. A torsion spring 43 is disposed on pin 47, as is best seen in FIG. 8, to bias the pawl 46 counterclockwise with respect to the lever 45, whereby the hook 46a will yieldably engage the ratchet teeth 37a as shown in FIG. 6. However, this operative interengagernent between hook 46a and teeth 37a can be prevented, and hence the racking mechanism will be disabled, by a stop member 49 which move, under circumstances that will later be explained,to an active position where it engages the tail 46b of pawl 46 and tiits the pawl clockwise against its bias, whereby the hook 46a is held off the teeth 37a, as shown in FIG. 5. The con: struction, operation and purpose of this disabling means will be fully explained following a description of the rest of the racking mechanism.

The lever 45 which carries pawl 46 is pivotally mounted on the shaft 39 adjacent to the ratchet wheel 3'7 for oscillatory movement with respect thereto. The lever is actuated in a clockwise direction, as viewed in FIGS. 5 and 6, by a cable 50 which runs over a pulley 51 rotatably mounted on a pin 52 projecting from lever 45 in quadrature with the pin 47. The pin 52 is located closer to the axis of shaft 39 than pin 47. It is apparent that the lever '45 in essence is a bell crank which, when pivoted clockwise, so moves the pawl 46 as to advance the ratchet wheel 37 in a clockwise direction. The lever is biased in a counterclockwise direction by a tension spring 53 connected between it and the stationary mounting plate 4t). The cable 56 and pulley 51 are part of the pulley sys tem 44. Opposite ends of cable 5% are respectively attached to two different rims of a double pulley 54. The double pulley 54 is rotatably disposed on a shaft 55 located directly under the pulley 5i, and as is best seen in FIG. 8, the ends of shaft 55 are anchored to the stationary bracket 25 and plate 40, respectively. I A stop pin 56 protrudes from the stationary plate 46 a short way from the shaft 55 and is disposed in a 330-degree concentric groove 57 formed in the side of the double pulley; consequently the rotation of this pulley is limited to 330 angular degrees.

In FIGS. 5 and 8 it is apparent that the double pulley 54 has one rim 54a of greater diameter than the adjoining rim 54b. One end of the cable 56 is affixed to the greater rim 54a. The cable then loops over the companion pulley 51 and is Wrapped in a counterclockwise sense once around the lesser rim 54b of the double pulley 54, with the end 501) of the cable being afiixed to the lesser rim at a point which is almost diametrically opposite the cable end 5tla. Upon rotating the double pulley through 330 degrees in a clockwise direction, from the starting position in which it is shown in FIG. 5 to an angular position shown in FIG. 6, the cable 56 is played out of the lesser rim 54b and is wrapped onto the greater rim 54a. Because of their different diameters, more cable is wrapped onto the greater rim 54a than leaves the lesser rim 54b, and the cable loop extending over the pulley 51 is therefore constricted. As a result of this differential pulley arragement, the driven pulley 51 is pulled downwardly by the cable (with a large mechanical advantage being realized), and the lever 45 to which it is at-- tached is tilted clockwise on shaft 39 through an angle of about 36 degrees, whereby the pawl 46 is actuated to advance the rotatable ratchet wheel 37 by a predetermined number of degrees.

Since the ratchet wheel 37 is keyed to the shaft39, the shaft also rotates to advance the companion ratchet wheel 38 through the same angular increment. As is shown in FIG. 7, the peripheral teeth 33a of the latter wheel are yieldably engaged by a holding-pawl 58. This pawl is pivotally supported by means of a pin 59 mounted on stationary plate 46, and a hooked end 58a thereof is biased into engagement with the ratchet teeth 38a of the wheel 38 by an appropriate tension spring 60. The holding pawl 58 in cooperation with the ratchet teeth Shaserves positively to prevent appreciable back-tracking (reverse rotation) of the cam members 37 and 38 while the ratchet operating pawl 46 returns from its FIG. 6 disposition to its starting position shown in FIG. 5.

In order to rotate the double pulley 54 in a clockwise direction, thereby advancing the camming members as explained above, a driving pulley 61 is mounted adjacent thereto on the shaft 55. The driving pulley 61, which can be seen in FIGS. 6 and 8, is connected to the T- handle 361 by means of the flexible cable 43 which is wrapped more than one full turn around its rim. By grasping the handle 361 andpulling on the cable 4?, the driving pulley 61 is rotated about its axis in a clockwise direction.

The diameter of the driving pulley rim is the same as that of the greater rim 54a of the double pulley 54. These two pulleys are operatively interconnected by lost-motion means comprising a pin 62 in an arcuate slot 63. The pin 62 is aflixed to the double pulley 54 from which it laterally protrudes, as is shown in FIG. 8. The arcuate slot 63 through which the pin 62 extends is located concentrically in the web of the adjacent pulley 61 as is shown in FIG. 6. The purpose of the lost motion coupling will be explained below. For now it is sufficient to understand that, as the driving pulley 61 is rotated in a clockwise direction (as viewed in FIGS. 5 and 6), the trailing end of the slot 63 engages the pin 62 of the double pulley 54 thereby operating the double pulley in the same direction through its limited 330-degree rotation.

The actuating handle 361 for the racking mechanism is seatable in a special insert or bushing 121 of mounting bracket I22. which preferably is affixed to the left side panel 162a of the extensible collar 102. An appropriate opening 123 in front cover I66 makes the handle 361 conveniently accessible from outside the breaker compart ment with the cover closed, as is indicated in FIGS. 1-3.

In order to carry out a racking operation, the handle 361 must successively be pulled as far away from the compartment cover as the attached cable 43 permits.

After each stroke of the handle it returns automatically to its seated position or terminus in the bushing 121. This return is caused by the reaction of two coil springs 6 t and 65, best seen in FIG. 8, which are disposed to bias the driving pulley 61 in a direction recalling the cable 43.

The coil spring 64, which is also partially visible in FIG. 6, is relatively strong. Its inner end is anchored to the pulley mounting shaft between the pulleys 54 and 61, and its outer end is fastened to the pin 62 which protrudes from the double pulley 54. This spring is disposed to urge the pin 62 in a counterclockwise direction, as viewed in FIGS. 5 and 6, whereby the double pulley is biased in a counterclockwisedirection to its starting position shown in FIG. 5. The pin 62 acting in the lost-motion slot 63 of the driving pulley 61 tends to turn the driving pulley in the same direction. The other coil spring 65 is fastened at its outer end to the distal end of pin 62, while its inner end is anchored to the hub of the driving pulley 61. This relatively weak spring is stressed upon angular movement of the driving pulley, relative to the pin 62, in a clockwise direction, and hence the pulley 61 is additionally biased in a counterclockwise direction toward an initial position in which the leading end of its slot 63 would engage the pin 62.

The purpose of a lost-motion coupling (comprising the pin 62 and a slot 63) between the driving pulley 61 and the double pulley 54 will now be apparent. As is illustrated in the drawings, the terminus of the operating handle 301 travels with the relatively movable unit 191 of the breaker housing, while the axis of the pulley mounting shaft 55- is fixed. Consequently, the free length of cable 43 extending between the handle terminus and the driving pulley varies-in dependence upon the position of the inner part 101 along its course or" reciprocating movement.- This length is shorter when the inner part is retracted than when extended. To compensate for such variance, the lost-motion slot 63 is provided, and its length is made approximately equal to the overall distance which the inner part 101- travels between opposite limits of its reciprocating movement. As a result, all variations in the free length of the cable 43 are accommodated by the driving pulley 61, and the double pulley 54 can be rotated from the same starting position through its full 330 degrees by every stroke of the handle 361.

In order more clearly to understand the manner in which the above-described racking mechanism drives the rectractable inner part 191 through its limited course of reciprocating movement, a rack-in operation of the mechanism will now be briefly described. For this particular purpose, no consideration is given to the automatically operative position stop means and the accompanying reset means for manually releasing the same. Their structure and operation, to be fully described soon hereinafter, can be disregarded here. In this connection, it should be assumed that the stop member 49: is in 21 released position out of engagement with the tail of pawl 46, and that nothing interferes with the rack-in operation being de scribed.

Before beginning the rack-in operation, the inner part 101' of the breaker compartment is in its extended position, and the removablebreaker unit is in its corresponding disconnect? or storage position. This is shown in FIG. 5, where the cam roller 41 of the racking mechanism, riding in the camming slot 119 of the supporting runner 103 of the retractable inner part .101, is seen to be located at the most frontwardly disposed point of its orbit. The double pulley 54, and hencethe oscillatory lever 45 of the racking mechanism are both shown in their starting positions in FIG. 5, and the racking handle 301 is at rest at its terminus in the bushing12'1.

The first step of the rack-in operation is begun by pulling the handle 301 from in front of the compartment so as to extend the cable 43 thereby rotating the driving pulley 61, and conjuctively the double pulley 54 which is coupled thereto, in a clockwise direction through 330 degrees. This constricts the cable loop 50, tilts the lever 45 clockwise, and so moves pawl 46 that the pawl drivingly engages one of the peripheral teeth 37a of the ratchet wheel 37 and advances this member through about 30 degrees. As a result the roller 41 is moved clockwise along its orbital path, thereby rising in the camming slot 119' and camming the runner 103 rearwardly. The same camming action takes place between. the other runner 1'84 and the companion camming member 38 which is keyed with member 37 to the common shaft 39. The disposition of the various parts of the racking mechanism at this point is illustrated in FIG. 6. It will be observed that the amount by which the inner part 101 of the compartment is it) retracted during the first step of the rack-in operation (and during each of the successive steps which follow) depends upon the radius of the orbital path, the particular angle of advancement of the cam roller, and the contour or profile of that portion of the camming slot which the roller traverses.

Upon completing the first stroke of the racking handle 301 (and each of the successive strokes which follow), the handle is allowed to return to its terminus. During this return the coil spring 64 effects counterclockwise rotation of the double pulley 54 toward its starting position, and the driving pulley 61 is correspondingly turned, thereby recalling the extended cable 43. Due to the differential rims on the double pulley, the loop of cable 50 is distended. Consequently the bias spring 53 now tilts the oscillatory lever 45 counterclockwise, and the ratchet operating pawl 46 returns to its starting position. Here it is again positioned for drivingly engaging another one of the peripheral teeth 37a which succeeds by about 30 angular degrees the one tooth previously engaged. The starting position or the double pulley 54, and hence the starting position of the lever 45, is determined by stop pin 56 which is located in the pulley groove 57. The lost-motion coupling comprising the pin 62 in slot 63 enables the driving pulley 61 to continue turning in the counterclockwise direction, under the influence of bias spring 65, until the racking handle 301 has attained its terminus.

Having now concluded the first step of the rack-in operation, the T-handle Bill is again pulled in order to con tinue the angular advancement of the camming members 37 and 38, whereby the inner part 101 is further retracted in a manner precisely the same as that described above. The ratchet teeth 37a have been so arranged that the inner part 101 will just reach its predetermined intermediate position, corresponding to th test position of the removable breaker unit, at the end of the second stroke of the handle;

Four more successive strokes of the racking handle 301 are required in order to drive the inner part 101 from its intermediate position to its retracted position shown in FIG. 7, wherein the removable circuit breaker unit resides in its connected or operating position. The cam rollers 4-1 and 42 of the racking mechanism have now been incrementally advanced to the most rearwardly disposed points of their respective orbits. During this final phase of the rack-in operation, the spring-loaded primary disconnect members 210 will engage the cooperating disconnect members 27, and consequently the frictional forces which resist and oppose movement of the inner part'are significantly increased. For the purpose of overcoming this increased back pressure without objectionably increasing the input energy required of the operator, the profile of the camming slots 119 and 120 has been designed to provide, in coopeartion with the rotatable camming members 37 and 38, respectively, appropriately increased mechanical advantage at those stages of travel of the inner part 101 where theback pressure is greatest.

As can be seen in FIG. 7, the holding pawl 58, which engages the peripheral teeth 38a of the camming member 33 to prevent back-tracking of the rotatable camming members during the rack-in operation, also helps hold the inner part 101 in its retracted position against mechanical and magnetic forces which tend to move the circuit breaker unit out of its operating position. Toward this end of the rear edge of each of the camming slots 119 and 120, substantially midway between the ends thereof, has been so inclined from Vertical as to establish in conjunction with the cooperating rollers 41 and 42. a reverse movement in the camming members 37 and 38. Because of this negative slope of the camming slot, any spurious attempt on the part of the inner part 101 to move from its retracted position tends to cause reverse or backward rotation of the camming member 38, but such rotation will be positively blocked by the holding pawl 58. Of course the retracted inner part may intentionally be extended by 1 ll carrying out a rack-out operation of the racking mechanism which, like the rack-in operation described above, requires six repeated strokes of the operating handle 301 to incrementally advance the rotatable camming members through another 180 degrees thereby driving the inner part 101 to its extended position shown in FIG. 5.

The ratchet wheel and pawl type racking mechanism that has been shown in the drawings and described hereinbefore is the claimed subject matter of a copending patent application S.N. 154,942, Netzel, filed on November 27, 1961, and assigned to the assignee of the present application. As will be apparent to those skilled in the art, this preferred mechanism is but one illustrative example of various means available for driving the movable unit 101 and circuit breaker 201 between different predetermined positions. For instance, a racking mechanism of the kind shown in US. Patent No. 3,005,064, Baird et al., granted on October 17, 1961, might be utilized, or alternatively, for a portion of its total travel, the breaker unit could be impelled by hand without the aid of any force-amplifying means.

Each of the operating (connected), test and storage (disconnect) positions of the circuit breaker unit, to which it is moved by operating the above-described racking mechanism, is distinctly and positively defined by releasable position stop means which will now be described. In the illustrated embodiment of my invention the position stop means comprises a stop member 124 which is mounted on a pin 125 affixed to the left-hand extensible runner 10.3 of the breaker supporting means for pivotal movement with respect theretoin cooperation with a notched slot 66 which is disposed in the stationary sidewall bracket 25 of the breaker housing. These parts are shown in FIGS. 8-10 and 12 of the drawings,

As can be seen in FIGS. 9, 10 and 12, the slot 66 in bracket has a horizontally elongated open portion, with three spaced-apart stops or position-determining notches 66c, 66t and 66d being formed in the bottom edge thereof. Thestop member 124, which as shown in FIGS. 8 and 12 is located on the opposite side of the bracket 25 from the runner 103, has a pin 126 which protrudes laterally therefrom into the slot 66 for releasably entering the notches 660, 661. and 66d as the pin moves into proximity respectively therewith during reciprocating movement of the runner 103. The pin 126, when approaching each notch in the slot 66, is biased downwardly therein by the action of a compression spring 127. As best seen in FIGS. 8 and 9, this spring is located on a spring guide rod or link 128 so as yieldably to urge a pin 129, which is aflixed to the stop member 124, away from a lug 130 affixed to the runner 103 therebelow. To permit pin 125 and the lug 130 which are carried by the runner 103 to pass through the stationary bracket 25 and move rectilinearly in unison with the runner, the pin 125 has been disposed at an appropriate elevation to travel freely in the open portion of the slot 66, and an additional slot 67 has been provided in bracket 25 to accommodate the lug 130, as is shown most clearly in FIGS. 9 and 12.

While this position stop means has been illustrated in a preferred form, there are other equivalent constructions which will occur to those skilled in the art. For example, the same result could be obtained by pivotallymounting and suitably biasing a notched member on the stationary sidewall of the breaker compartment for receiving a cooperating pin carried by p the movable runner which supports the breaker.

The notches 66c, 66! and 66d of the position stop arrangement shown in the drawings and described above are discretely located so that the stop member 124 will automatically move to an angular position where pin 126 occupies one of these notches, thereby to physically block movement of the runner 103 and hence effectively prevent further movement of the circuit breaker supporting Cit means, when the retractable inner part 101 of the breaker compartment reaches each of its three predetermined positions (retracted, intermediate and extended, respectively) corresponding to the connected, test and disconnect positions of the circuit breaker unit; For example, when the breaker unit is in its disconnect position, as indicated in FIG. 9, the stop member 124 will be pivoted about the axis of pin 125 bythe bias spring 127 to the active or blocking position shown, with pin 126 releasably locked in the notch 66d. So long as the stop means is thus disposed, the inner part 101 and the circuit breaker 201 supported thereby are held in their obtained positions. They cannot be moved from such position until the stop means has been released. a

In order to release the stop means and thereby enable the inner part 101 to be moved to its succeeding position, I provide a manually operative reset mechanism which will now be described. This mechanism is mounted on the extensible collar 102 and is so coupled to the stop member 124 as to tilt this member from the active position thereof to a released position, wherein the pin 126 is removed from the notch 66c, 66f or 66d which it formerly occupied, when desired.

The reset mechanism, as best seen in FIGS. 5, 6 and 12, comprises an elongated push rod or bar 131 slidably mounted on the breaker supporting means above the runner 103 for rectilinear movement relative thereto. The rear end of the push rod 131 is connected to the stop member 124 by means of a pin 132 which projects lat erally from the rod through a narrow horizontal slot 68 in the stationary sidewall bracket 25 and into a short vertically disposed slot 133 located in the member 124. (See FIGS. 8, 9 and 12). The rod 131 includes a guide slot 134 which slidably embraces a supporting pin 135 alfixed to the left-side panel 102a of the collar 102, and the forward end of the rod is pinned at 136 to the upper end of a direction changing lever 137 which is pivotally mounted at 138 on the'runner 103. The lower end of lever 137 is linked at 139 to a rodlike member 140 which is slidably disposed in a bushing 141 carried by the mounting bracket 122. The member 140 extends through the opening 123 in the front cover 106 of the breaker compartrnent, and it is terminated outside the housing by a conveniently accessible reset knob 142.

The push rod 131 is impelled frontwardly by the stop member 124, as its pin 126 enters a position-determining notch in slot 66, to the foremost position of the rod which is shown in FIG. 5. Consequently the reset knob 142 is in whenever the position stop means is in a movement-blocking disposition (FIGS. 8 and 9). By manually pulling the knob 142 to an on or reset position (142a) in FIG. 6), the lever 137 is pivoted in a clockwise direction thereby shifting the push rod 131 rearwardly with respect to the runner 103. The pin 132 projecting from the push rod moves the stop member 124 from its active position against the force of the bias spring 127, and pin 126 of the stop member willbe lifted from the bottom of the cooperating position-determining notch. The

stop member is thus moved to another angular position where its pin 126 is removed from a position-determining notch 660, 661, or 66d and occupies one of a series of three notches 690, 691 and 69d provided along the top edge of the slot 66. (See FIG. 10 for example.) In this manner the top means is released or unblocked to permit continued movement of the retractable inner part 101 and the circuit breaker 201 carried thereby to their next position. i

As is taught in the aforesaid Netzel application S.N. 154,960, the releasable stop means described herein before has associated therewith'additional means for automatically disabling the racking mechanism when the movable unit 101 reaches each of its predetermined positions. This belt and suspender arrangement offers the advantage of insuring against undesirable loading of not only the position stop means 66, 124-26 but also the 13 operating means 43-46 which drives the camming member 37 of the racking mechanism. In other words, should an operator in carrying out a rack-in or rack-out operation of the circuit breaker thoughtlessly attempt to continue such. operation, after reaching the test position, without first manipulating the reset knob 142 to release the position stop means, no damage will be done to any of the pins, levers, pulleys and other parts of the illustrated stop means and racking mechanism. On the other hand, without the disabling provision referred to there would be areal possibility that a forceful misoperation of this kind might bend or otherwise damage some of these parts.

The. racking mechanism is disabled, and operation of the camming member 37 by the T-shaped actuating handle 301 is consequently prevented, in response to movement of the stop member 124 to its active position (FIGS. 5, 8 and 9) when the inner part 101 arrives at any one of its three predetermined positions. Although a more direct coupling between member 124 and the racking mechanism would be suitable for this purpose, a linkage utilizing the push rod 131 and the stop member 49 is preferred. It is illustrated most clearly in FIG. 12.

The stop member 49 of this preferred linkage is pivotally' mounted on a pin 71 which is afiixed to the stationary sidewall bracket 25 of the breaker compartment, and the push rod 131 is provided with a horizontally elongated slot 143 through which the pin 71 extends. Three spaced-apart notches 143e, 143t, and 14312 are formed in the bottom edge of the slot 143. The stopmember 49 includes a pin 72 which protrudes laterally therefrom into the slot 143 where it will enter an appropriate one of the notches 143c 1431? and 143d, under the influence of a biasing spring 73, whenever the inner part 101 of the breaker compartment is in one of its three predetermined positions and the push rod 131 has been impelled to its foremost position (indicating that the position stop member 124 is in a movement-blocking disposition). With the pin 72 disposed in one of the notches of slot 143, the stop member 49 is tilted, as shown in FIG. 5, to an angular position wherein it engages the tail 46b of the pawl 46 and so tilts the pawl as to prevent its hooked end 46a from engaging the ratchet teeth 37a of the camming member 37. This movement of member 49 to its active position will render the cam roller 41 of member 37 incapable of coacting with the slotted block 117 of runner 103 for the purpose of driving the inner part 101 from its obtained position, and continued movement of the inner part is effectively prevented.

In order to return the stop member 49 to a non-disabling or released position (in which it is shown in FIGS. 6 and 12), the forward side 144 of each notch 143e, 1431, 143d in the push rod 131 is inclined as shown. An inclined side 144 will cam the pin 72 upwardly out of the notch in which it was residing, thereby moving the member 49 clockwise in opposition to the bias provided by spring 73, as the push rod is shifted rearwardly during manual operation thereof. It is therefore apparent that,

by manually pulling the reset knob 142 to its reset position, the stop member 49 is reset and the pawl 46 is again enabled to operate the camming member 37.

In accordance with my invention, the stop means and the reset means described hereinbefore are so constructed and arranged that the stop means, after being released by manual operation of the reset knob 142, will be maintained released even though the operator lets go of the reset knob. In other words, I provide means responsive 'to stop-means-releasing operation of the push rod 131 for maintaining the respective stop members 124 and 49 in their released dispositions-until the inner part 101 is moved from its obtained position. Such an arrangement is advantageous in that the operator, after pulling the reset knob 142, does not have to continue holding this knob in order to resume movement of the circuit breaker into or out of the breaker compartment.

In the preferred embodiment of my invention, the above-mentioned function is obtained by disposing the stop member 124 and its bias spring 127 so that this stop member is bidirectionally biased. With reference to FIGS. 9 and 10, the stop member 124 and spring guide link 12% are seen in essence to be an overcenter toggle combination, with pin 129 comprising the knee of the toggle. The resetting operation referred to above not only eifects movement of the position stop member (counterclockwise from its FIG. 9 disposition) until pin 126 is released from a position-determining notch in slot 66, but it further tilts the stop member (to its FIG. 10 disposition) and thereby causes the toggle knee 129 to move past dead center with respect to a straight line connecting the axes of pin and lug 130. As a result of this overcenter movement by the toggle, the effective direction of the bias provided by the compression spring 127 is now reversed, and the pin 126 is yieldably urged upwardly against the top edge of slot 66 which is notched at 690, 691 and 69d for this purpose. Consequently the push rod 131 will be retained or latched in its rearwardly shifted position, and the reset knob 142 is held in its reset position. Both of the stop members 124' and 49 are then maintained in their released or inactive positions while the circuit breaker remains in the particular position to which it had previously been moved.

In order to effect a change in the direction of the bias torque of stop member 124 after the resetting thereof, so that the pin 126 will be predisposed automatically to enter the next succeeding position-determining notch in the bottom edge of slot 66 of the stationary sidewall bracket 25 (for movement-stopping purposes), the upper surface of this slot depends between the notches 69c, 69t and 69d and the notch sides 70 are declined as is shown in FIGS. 9, 10 and 12. A declined side 70 serves to earn the pin 126 downwardly, and hence tilt the cam member 124, in responseto movement of the inner part 101 of the breaker compartment from any one of its three predetermined positions, whereby the toggle knee 129 is returned through dead center and the compression spring 127 again urges the pin 126 downwardly against the bottom edge of the slot 66. After this overcenter. movement by the toggle, and while the pin 126 is approaching the next positiondetermining notch 66c, 66t and 66d, the stop member 124 will travel in an intermediate, passive disposition approximately half way between its released and active positions shown in FIGS. 10 and 9, respectively. Consequently the push rod 131 and its reset knob 142 will be moved, relative to their supporting runner 103 and collar 102, to intermediate positions which are substantially midway between reset and those shown in FIG. 5. These parts are seen in their intermediate positions in FIGS. 6 and 12.

The position'stop member 124 is prevented from returning all the way to its active position whenever the breaker supporting unit 101 is located between predetermined positions thereof by the bottom horizontal edge of the slot 66. The pin 126 of member 124 of course cannot enter a position-determining notch 66c, 66t and 66d before the breaker unit is moved to the corresponding one of its connected, test and disconnect positions. I also provide means for preventing the racking-mechanism-disabling stop member 49 from prematurely returning to its active position as the movable unit is moving between the predetermined positions thereof. Toward this end, as is best seen in FIG. 12, the extensible runner 103 of unit 101 is equipped with a raised shoulder 145 having spaced-apart indentations 145e, 145t and 145d along its upper edge. The pin 72 of member 49 moves to a position directly over these respective indentations only when the circuit breaker unit attains its connected, test and disconnect positions, respectively, and consequently the raised shoulder 145 does not interfere with the abovedescribed disabling action which will take place each time the push rod 131 is impelled frontwardlyby operation of the position-determining means. But the raised portions of the shoulder 145 between indentations there in, being slidably engaged by the pin 72, will keep the stop member 49 in its released position whenever the breaker unit is located between the aforesaid positions, even though pin 72 rides over one of the notches in slot 143 of the push rod 131 which is then in its intermediate disposition, as shown in FIGS. 6 and 12, for example.

As the circuit breaker unit arrives at each of its predetermined positions, the pin 126 of the stop member 124 becomes aligned with a position-determining notch 660, Mr or 66d, and the stop means operates automatically in response thereto. As the pin 126 enters the aligned notch, the connected push rood 131 is impelled frontwardly to its foremost position. This retracts the reset knob 142 which then assumes its in position, indicating visually that one of the three predetermined positions of the breaker supporting means has just been reached. Manual operation of the reset mechanism is again required in order to release the stop means and permit continued movement of the retractable inner part 1111. If for any reason desired, the push rod 131 can be manually returned to its foremost position so long as the breaker unit has not been moved from its obtained position.

According to my invention, the push rod 131 of the reset mechanism has other means associated therewith to effect conventional breaker interlock functions which may be summarized as follows: (1) to prevent initial movement of the breaker supporting unit 101 if the circuitinterrupting contacts of the circuit breaker 201 are closed, and (2) to prevent closing of the circuit breaker while the breaker unit is being moved. Toward this end, the push rod 131, as is shown in FIGS. 5, 6, 11 and 12, includes (l) a laterally projecting interlock tab 146 located near the forward end of a rectangular opening 147 therethrough, and (2) a laterally offset interlock element 1418 of trapezoidal shape, the front and rear sides (148a and 14%) of which provide inclined camming surfaces.

The circuit breaker 2111 (see FIGS. 4, 5, 6 and 11) is equipped with cooperatinginterlock elements comprising: (1) a pivotally disposed upstanding link 212 actuated in response to circuit-closing movement of a switch member 213 of the breaker, and (2) a vertically movable tripping link 214 which is coupled to a trip latch shaft 215 for actuating the same when lifted. While the various circuit breaker parts which are connected to the switch member 213, being entirely conventional, have not been shown in the drawings, it will be understood by those skilled in the art that the switch member is moved from the broken-line position shown in FIG. 11 to the higher dot-dash-line position shown in the same figure during a closing operation of circuit-interrupting contact of the breaker. It will further be understood that the trip latch shaft 215, upon being tilted from the angular position in which it is shown in FIG. 5 to its FIG. 6 disposition, is so interconnected with the contact mechanism of the circuit breaker 201 as to effect tripping of the breaker and also to prevent subsequent closure of the circuit-interrupting contacts in a conventional manner.

In order to accomplish the first breaker interlocking function referred to, the interlock link 212 is bent over at its upper end 212a so as to move behind the tab 146 of the reset push rod 131 and prevent rearward movement thereof whenever the circuit breaker 201 is closed. It is apparent in FIGS. 5 and 11 that this obstructs stopmeans-releasing operation of the push rod 131, whereby the position stop means will hold the retractable innerpart 1111 in its obtained position and the racking mechanism remains disabled. On the other hand, the bent over end 212a of the interlock link 212 is tilted out of the way of the tab 146 whenever the circuit breaker 2111 is open,

' thereby enabling the stop means to be released and a racking operation to be undertaken.

In order to accomplish the second breaker interlock lock element 14-8 carried by the push rod 131. With the push rod 131 in its foremost position, as is shown in FIG. 5, the pin 217 is disposed immediately behind side 1415b of the element 148, and as a result the link 214 is in a lowered position which enables the trip latch shaft 215 to assume its non-tripping angular position. The circuit breaker 2111 can now be closed at will. Upon manipulating the reset knob 142 to reset the position stop means and render the racking mechanism operable, however, the push rod 131 is shifted rearwardly thereby causing the rear camming surface 14% of the element 148 to elevate pin 217, whereby the link 214 is lifted to actuate the trip latch shaft 215 of the circuit breaker 2111. So long as the push rod 131 is reset or is in its intermediate position (FIGS. 6 and 12), as it will be while the circuit breaker is moving along its course between predetermined positions thereof, the tripping interlock link 214 will hold the trip latch shaft in its FIG. 6 disposition, thereby preventing closure of the circuit-interrupting contacts of the breaker.

The push rod 131 of the reset mechanism of my invention can also be utilized to provide additional locking and interlocking functions if'desired. For example, the hinged door 1116 of'the breaker compartment could be interlocked with the enclosed'circuit bre'aker to prevent opening of the door unles the breaker has first been tripped-by mounting on the side panel 102a of the inner part 101 a suitable link disposed in cooperation with both the latchbar 108 of the door latching mechanism and the forward end of the push rod 131, with the link being arranged to prevent raising of the latchbar 188 for unlatching the door until the push rod 131 is shifted rearwardly by a resetting operation thereof. Another example has been illustrated in FIG. 12 where a recess 149 is shown in a flanged portion of the forward end of the push rod 131, the recess 149 being disposed under a key-operated lock 150'mounted on the side panel 102a of the inner part 101. The lock 150 is so oriented that its bolt 151 can be extended downwardly into the recess 149 only when the push'rod '131 is' in its foremost position, and when thus extended the bolt 151 effectively prevents rectilinear movement of the push rod, whereby the releasable stop means described hereinbefore cannot be reset and the circuit breaker is locked in its obtained position. If desired, this locking function could be limited to only the'test and disconnect positions of the breaker by making the position-determining notches 661 and 66d deeper than the companion notch 66c and by appropriately arranging for the push rod 131 to be impelled an extra dis tance frontwardly when pin 126 of stop member 124 falls into either of these deeper notches 66t and 66d.

While a preferred form of the invention has been shown and described by Way of illustration, many modifications will occur to those skilled in the art. I therefore contemplate by the claims which conclude this specification to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination:

(a) a relatively stationary enclosure unit;

(b) a movable unit located in the enclosure unit, said enclosure unit including means for supporting said movable unit for reciprocating movement between a first position within said enclosure unit and a second position spaced apart from said first position;

(c) means for driving said movable unit between said first and second positions; 7

(d) releasable stop means operative automatically when said movable unit reaches said second position for preventing continued movement of the movable unit until released;

(e) manually operative reset means for releasing said stops means; and

(f) means effective upon stop-means-releasing operation of said reset means to maintain said stop means released while said movable unit remains in its second position.

2. In combination:

(a) a relatively stationary enclosure unit;

(b) a cooperating movable unit located in the enclosure unit, including means for supporting said movable unit for reciprocating movement between two predetermined positions at least one of which is within said enclosure unit;

(c) a racking mechanism for moving said movable unit relative to said enclosure unit;

(d) a releasable stop means operative automatically in response to said movable unit reaching each of said predetermined positions to disable said racking mechanism and hold said movable unit in its obtained position, whereby the stop means must be released before the movable unit can be moved from either one of said positions;

(e) manually operative reset means for releasing said stop means; and

(f) means associated with said reset means for preventing said automatic operation of said stop means after the reset means has been operated and before the movable unit is moved to another of said predetermined positions.

3. In combination:

(a) a movable unit;

(b) a relatively stationary enclosure unit in which said movable unit is located, said enclosure unit including means for supporting the movable unit for reciprocating movement between a predetermined first position in the enclosure unit and a second position spaced apart from said first position; and

(c) means for determining said second position of said movable unit comprising (i) a stop member,

(ii) means for movably mounting said stop member on a predetermined one of said units,

(iii) the other one of said units including means for enabling the stop member to move between an active position and a released position whenever the movable unit is in its second position,

(iv) means for preventing movement of the movable unit relative to the enclosure unit when the former is in its second position and the stop member is in its active position and for permitting such movement when the stop member is moved to its released position,

(v) bidirectionally effective bias means for urging the stop member toward its active position as said movable unit approaches said second position and for yieldably maintaining the stop member, upon movement thereof from its active position to its released position, in said rereleased position, and

(vi) reset means for moving said stop member from its active position to its released position.

4. The combination of claim 3 in which means responsive to movement of the movable unit is provided for effecting a change in the direction of bias applied by the bias means to the stop member.

5. An enclosure for an electric circuit breaker equipped with a movable switch member comprising:

(a) a relatively stationary compartment;

(b) said compartment including means for guiding and for moving the circuit breaker along a course of reciprocating movement between a first position within the compartment and a second position spaced apart from said first position;

(c) releasable position determining means operative automatically when the circuit breaker reaches said second position to stop movement of the circuit breaker;

(d) manually operative reset means for releasing said position determining means, thereby permitting movement of the circuit breaker; and

(e) interlock means associated with said reset means and adapted to cooperate with the switch member of the circuit breaker, for preventing releasing operation of the reset means when the circuit breaker is closed.

6. An enclosure for an electric circuit breaker equipped with a movable trip member comprising:

(a) a relatively stationary compartment (b) means in said compartment for guiding and for moving the circuit breaker along a course of reciprocating movement to and from a connected position within said compartment;

(0) releasable stop means for preventing movement of the circuit breaker when the circuit breaker reaches a predetermined test position along the course of movement;

(d) a manual reset member associated with said stop means, said reset member being mounted in said compartment for movement from a first position to a second position for releasing said stop means and thereby permitting movement of the circuit breaker;

(e) an interlock member carried by said reset member where it cooperates with the trip member of the circuit breaker to prevent closure of the circuit breaker when said reset member is out of its first position; and

(f) means associated with said reset member for preventing the return thereof to said first position whenever the circuit breaker is located between said test and connected positions.

7. An enclosure for an electric circuit breaker compris- (a) a relatively stationary compartment having an opening therein, the compartment including an extensible inner part fitted into said opening for reciprocating movement between retracted and extended positions, said inner part including means adapted to support the circuit breaker;

(b) an openable access cover attached to said inner part for closing said opening;

(0) a racking mechanism associated with said compartment for moving said inner part;

(d) releasable stop means operative automatically when said inner par-t reaches either of said retracted and extended positions for preventing continued movement thereof;

(e) a push rod mounted on said inner part in cooperation with said stop means, said push rod being movable from a first position to a second position to release said stop means and thereby permit movement of said inner part from its obtained position;

(i) means manually operative from outside said compartment with said access cover closed for moving said push rod from its first to its second position;

(g) means responsive to said movement of said push rod to maintain said push rod in said second position so long as said inner part remains in its obtained position; and

(h) means responsive to movement of said inner part for moving said push rod from said second position to an intermediate position from which it is movable to said first position upon automatic operation of said stop means when said inner part reaches the next one of its retracted and extended positions.

References Cited by the Examiner UNITED STATES PATENTS 2,777,024 1/57 West 200-50 ROBERT K. SCHAEFER, Acting Primary Examiner.

7 BERNARD A. GILHEANY, Examiner. 

1. IN COMBINATION: (A) A RELATIVELY STATIONARY ENCLOSURE UNIT; (B) A MOVABLE UNIT LOCATED IN THE CLOSURE UNIT, SAID ENCLOSURE UNIT INCLUDING MEANS FOR SUPPORTING SAID MOVABLE UNIT FOR RECIPROCATING MOVEMENT BETWEEN A FIRST POSITION WITHIN SAID ENCLOSURE UNIT AND A SECOND POSITION SPACED APART FROM SAID FIRST POSITION; (C) MEANS FOR DRIVING SAID MOVABLE UNIT BETWEEN SAID FIRST AND SECOND POSITIONS; (D) RELEASABLE STOP MEANS OPERATIVE AUTOMATICALLY WHEN SAID MOVABLE UNIT REACHES SAID SECOND POSITION FOR PREVENTING CONTINUED MOVEMENT OF THE MOVABLE UNIT UNTIL RELEASED; (E) MANUALLY OPERATIVE RESET MEANS FOR RELEASING SAID STOPS MEANS; AND (F) MEANS EFFECTIVE UPON STOP-MEANS-RELEASING OPERATION OF SAID RESET MEANS TO MAINTAIN SAID STOP MEANS RELEASED WHILE SAID MOVABLE UNIT REMAINS IN ITS SECOND POSITION. 